Mips have delayslots for certain instructions
like jumps and branches. These are instructions
that follow the branch or jump and are executed
before the jump or branch is completed.
Early Mips compilers could not cope with delayslots
and left them up to the assembler. The assembler would
fill the delayslots with the appropriate instruction,
usually just a nop to allow correct runtime behavior.
The default behavior for this is set with .set reorder.
To tell the assembler that you don't want it to mess with
the delayslot one used .set noreorder.
For backwards compatibility we need to support
.set reorder and have it be the default behavior in the
assembler.
Our support for it is to insert a NOP directly after an
instruction with a delayslot when in .set reorder mode.
Contributer: Vladimir Medic
llvm-svn: 180584
This patch allows the Mips assembler to parse and emit nested
expressions as instruction operands. It also extends the
expansion of memory instructions when an offset is given as
an expression.
Contributer: Vladimir Medic
llvm-svn: 179657
This patch allows the assembler to recognize $fcc0
as a valid register for conditional move instructions.
Corresponding test cases have been added.
Contributer: Vladimir Medic
llvm-svn: 179567
Normally r_info is just a 32 of 64 bit number matching the endian of the rest
of the file. Unfortunately, mips 64 bit little endian is special: The top 32
bits are a little endian number and the following 32 are a big endian one.
llvm-svn: 178694
This finally fixes the encoding. The patch also
* Removes eh-frame.ll. It was an unnecessary .ll to .o test that was checking
the wrong value.
* Merge fde-reloc.s and eh-frame.s into a single test, since the only difference
was the run lines.
* Don't blindly test the content of the entire .eh_frame section. It makes it
hard to anyone actually fixing a bug and hitting a difference in a binary
blob. Instead, use a CHECK for each field and document what is being checked.
llvm-svn: 178615
Revision 177141 caused a regression in all but
mips64 little endian. That is because none of the
other Mips targets had test cases checking the
contents of the .eh_frame section. This patch fixes
both the llvm code and adds an assembler test case
to include the current 4 flavors.
The test cases unfortunately rely on llvm-objdump. A
preferable method would be to use a pretty printer output
such as what readelf -wf <elf_file> would give.
I also changed the name of the test case to correct a typo.
llvm-svn: 178506
Mips assembler supports macros that allows the OR instruction
to have an immediate parameter. This patch adds an instruction
alias that converts this macro into a Mips ORI instruction.
Contributer: Vladimir Medic
llvm-svn: 178316
Mips assembler allows following to be used as aliased instructions:
jal $rs for jalr $rs
jal $rd,$rd for jalr $rd,$rs
This patch provides alias definitions in td files and test cases to show the usage.
Contributer: Vladimir Medic
llvm-svn: 178304
For mips a branch an 18-bit signed offset (the 16-bit
offset field shifted left 2 bits) is added to the
address of the instruction following the branch
(not the branch itself), in the branch delay slot,
to form a PC-relative effective target address.
Previously, the code generator did not perform the
shift of the immediate branch offset which resulted
in wrong instruction opcode. This patch fixes the issue.
Contributor: Vladimir Medic
llvm-svn: 177687
This patch uses the generated instruction info tables to
identify memory/load store instructions.
After successful matching and based on the operand type
and size, it generates additional instructions to the output.
Contributor: Vladimir Medic
llvm-svn: 177685
The .set directive in the Mips the assembler can be
used to set the value of a symbol to an expression.
This changes the symbol's value and type to conform
to the expression's.
Syntax: .set symbol, expression
This patch implements the parsing of the above syntax
and enables the parser to use defined symbols when
parsing operands.
Contributor: Vladimir Medic
llvm-svn: 177667
The constructs %hi() and %lo() represent the high and low 16
bits of the address.
Because the 16 bit offset field of an LW instruction is
interpreted as signed, if bit 15 of the low part is 1 then the
low part will act as a negative and 1 needs to be added to the
high part.
Contributer: Vladimir Medic
llvm-svn: 175707
excluding visibility bits.
Mips specific standalone assembler directive "set at".
This directive changes the general purpose register
that the assembler will use when given the symbolic
register name $at.
This does not include negative testing. That will come
in a future patch.
A side affect of this patch recognizes the different
GPR register names for temporaries between old abi
and new abi so a test case for that is included.
Contributer: Vladimir Medic
llvm-svn: 175686
excluding visibility bits.
Mips (o32 abi) specific e_header setting.
EF_MIPS_ABI_O32 needs to be set in the
ELF header flags for o32 abi output.
Contributer: Reed Kotler
llvm-svn: 175569
excluding visibility bits.
Mips (Mips16) specific e_header setting.
EF_MIPS_ARCH_ASE_M16 needs to be set in the
ELF header flags for Mips16.
Contributer: Reed Kotler
llvm-svn: 175566
and enables the instruction printer to print aliased
instructions.
Due to usage of RegisterOperands a change in common
code (utils/TableGen/AsmWriterEmitter.cpp) is required
to get the correct register value if it is a RegisterOperand.
Contributer: Vladimir Medic
llvm-svn: 174358
but I cannot reproduce the problem and have scrubed my sources and
even tested with llvm-lit -v --vg.
Support for Mips register information sections.
Mips ELF object files have a section that is dedicated
to register use info. Some of this information such as
the assumed Global Pointer value is used by the linker
in relocation resolution.
The register info file is .reginfo in o32 and .MIPS.options
in 64 and n32 abi files.
This patch contains the changes needed to create the sections,
but leaves the actual register accounting for a future patch.
Contributer: Jack Carter
llvm-svn: 172847
but I cannot reproduce the problem and have scrubed my sources and
even tested with llvm-lit -v --vg.
Removal of redundant code and formatting fixes.
Contributers: Jack Carter/Vladimir Medic
llvm-svn: 172842
but I cannot reproduce the problem and have scrubed my sources and
even tested with llvm-lit -v --vg.
The Mips RDHWR (Read Hardware Register) instruction was not
tested for assembler or dissassembler consumption. This patch
adds that functionality.
Contributer: Vladimir Medic
llvm-svn: 172685
Hope you are feeling better.
The Mips RDHWR (Read Hardware Register) instruction was not
tested for assembler or dissassembler consumption. This patch
adds that functionality.
Contributer: Vladimir Medic
llvm-svn: 172579
we need to generate a N64 compound relocation
R_MIPS_GPREL_32/R_MIPS_64/R_MIPS_NONE.
The bug was exposed by the SingleSourcetest case
DuffsDevice.c.
Contributer: Jack Carter
llvm-svn: 172496
register names in the standalone assembler llvm-mc.
Registers such as $A1 can represent either a 32 or
64 bit register based on the instruction using it.
In addition, based on the abi, $T0 can represent different
32 bit registers.
The problem is resolved by the Mips specific AsmParser
td definitions changing to work together. Many cases of
RegisterClass parameters are now RegisterOperand.
Contributer: Vladimir Medic
llvm-svn: 172284
value in the 64 bit .eh_frame section.
It doesn't however allow exception handling to work
yet since it depends on the correct relocation model
being set in the ELF header flags.
Contributer: Jack Carter
llvm-svn: 171881
This patch provides support for the MIPS relocations:
*) R_MIPS_GOT_HI16
*) R_MIPS_GOT_LO16
*) R_MIPS_CALL_HI16
*) R_MIPS_CALL_LO16
These are used for large GOT instruction sequences.
Contributer: Jack Carter
llvm-svn: 168471
Note: [D]M{T,F}CP2 is just a recommended encoding. Vendors often provide a
custom CP2 that interprets instructions differently and may wish to add their
own instructions that use this opcode. We should ensure that this is easy to
do. I will probably add a 'has custom CP{0-3}' subtarget flag to make this
easy: We want to avoid the GCC situation where every MIPS vendor makes a custom
fork that breaks every other MIPS CPU and so can't be merged upstream.
llvm-svn: 165711
This patch provides initial implementation of load address
macro instruction for Mips. We have implemented two kinds
of expansions with their variations depending on the size
of immediate operand:
1) load address with immediate value directly:
* la d,j => addiu d,$zero,j (for -32768 <= j <= 65535)
* la d,j => lui d,hi16(j)
ori d,d,lo16(j) (for any other 32 bit value of j)
2) load load address with register offset value
* la d,j(s) => addiu d,s,j (for -32768 <= j <= 65535)
* la d,j(s) => lui d,hi16(j) (for any other 32 bit value of j)
ori d,d,lo16(j)
addu d,d,s
This patch does not cover the case when the address is loaded
from the value of the label or function.
Contributer: Vladimir Medic
llvm-svn: 165561
macro instruction (li) in the assembler.
We have identified three possible expansions depending on
the size of immediate operand:
1) for 0 ≤ j ≤ 65535.
li d,j =>
ori d,$zero,j
2) for −32768 ≤ j < 0.
li d,j =>
addiu d,$zero,j
3) for any other value of j that is representable as a 32-bit integer.
li d,j =>
lui d,hi16(j)
ori d,d,lo16(j)
All of the above have been implemented in ths patch.
Contributer: Vladimir Medic
llvm-svn: 165199
.set option
The patch implements following options
at - lets the assembler use the $at register for macros,
but generates warnings if the source program uses $at
noat - let source programs use $at without issuingwarnings.
noreorder - prevents the assembler from reordering machine
language instructions.
nomacro - causes the assembler to print a warning whenever
an assembler operation generates more than one
machine language instruction.
macro - lets the assembler generate multiple machine instructions
from a single assembler instruction
reorder - lets the assembler reorder machine language
instructions to improve performance
The above variants are parsed and their boolean values set or unset.
The code to actually use them will come later.
Following options are not implemented yet:
nomips16
nomicromips
move
nomove
Contributer: Vladimir Medic
llvm-svn: 165194
The assembler can alias one instruction into another based
on the operands. For example the jump instruction "J" takes
and immediate operand, but if the operand is a register the
assembler will change it into a jump register "JR" instruction.
These changes are in the instruction td file.
Test cases included
Contributer: Vladimir Medic
llvm-svn: 163368
Actually these are just stubs for parsing the directives.
Semantic support will come later.
Test cases included
Contributer: Vladimir Medic
llvm-svn: 163364
